Portable booster seat



FIG. 1 is a top, front, left perspective view of a portable booster seatshowing my new design;

FIG. 2 is a left side elevational view thereof, the right side of whichcorresponds;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top view thereof; and

FIG. 5 is a bottom view thereof.

The ornamental design for portable booster seat, substantially as shownand described.